There is a structure shown in FIGS. 14 to 16 as an example of a conventionally known current detection device. The current detection device 301 includes a bus bar 302, a printed circuit board 330 on which a Hall element is mounted, a magnetic member 304 for concentrating the magnetic flux, and a housing 305 for holding these components. The current detection device 301 detects a current value flowing through the bus bar 302 in such a manner that when a current flows in the bus bar 302 and a magnetic field is generated around, the Hall element outputs a voltage corresponding to a strength of the magnetic field (for example, refer to Patent Document 1).
The current detection device 301 fixes a bus bar 302 and the magnetic member 304 in such a manner that the printed circuit board 330, the bus bar 302 and the magnetic member 304 are in order assembled to the housing 305 before by thermally-welding the retaining portions 351 and 352 provided on the housing 305.
The retaining portion 351 is a portion for fixing the bus bar 302, and before the thermal welding is, as indicated by a one-dot chain line in FIG. 16, formed in a cylindrical shape with a smaller diameter than a round hole 320 formed through the bus bar 302. The retaining portion 351 fixes the bus bar 302 by passing through the round hole 320 and heating and pressing so that a distal end portion becomes a shape with a larger diameter than the round hole 320 as shown by a solid line in FIG. 16.
The retaining portion 352 is a portion for fixing the magnetic member 304 and before thermal welding is, as shown by a one-dot chain line in FIG. 16, formed in a plate shape extending in a height direction of the housing 305. The retaining portion 352 is heated and bent at a right angle, whereby the magnetic member 304 presses a bottom plate portion of the member 304 and fixes the magnetic member 304.